net: sctp: prevent writes to cookie_hmac_alg from accessing invalid memory
proc_dostring() needs an initialized destination string, while the one
provided in proc_sctp_do_hmac_alg() contains stack garbage.
Thus, writing to cookie_hmac_alg would strlen() that garbage and end up
accessing invalid memory.
Fixes: 3c68198e7 ("sctp: Make hmac algorithm selection for cookie generation dynamic")
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 26d50c5..3e0fc51 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -320,7 +320,7 @@
struct ctl_table tbl;
bool changed = false;
char *none = "none";
- char tmp[8];
+ char tmp[8] = {0};
int ret;
memset(&tbl, 0, sizeof(struct ctl_table));